Mitigate, whose central meaning is “to lessen” or “to make less severe,” is sometimes confused with militate, which means “to have effect or influence; weigh on.” This mix-up often occurs in the use of the phrase mitigate against, as follows: This criticism in no way mitigates (read militates) against your going ahead with your research. Although this use of mitigate occasionally occurs in edited writing, it is rare and is widely regarded as an error.